put down in black and white

put (something) down in black and white

To write something down as a means of making it official, legitimate, or binding. They promised to give me a raise when the project is complete, but I want them to put it down in black and white first. Make sure you have them put the deal in black and white before you agree to anything. That's a pretty generous offer—care to put it down in black and white?
See also: and, black, down, put, white
Farlex Dictionary of Idioms.

put something down in black and white

 and set something down in black and white
Fig. to write down the terms of an agreement; to draw up a written contract; to put the details of something down on paper. (Alludes to black ink and white paper.) We agree on all the major points. Now, let's set it down in black and white. I think I understand what you are talking about, but we need to put down the details in black and white.
See also: and, black, down, put, white
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • get (something) down in black and white
  • put (something) down in black and white
  • put (something) down in writing
  • set (something) down in black and white
  • set (something) down in writing
  • get (something) in black and white
  • write down
  • put pen to paper
  • splice (something) to (something else)
  • splice to